The present invention relates to a computer keyboard. Particularly, this invention relates to a key switch mounted on a computer keyboard.
A key includes a key top and a key switch on which the key top is mounted. The key top is an element touchable by a finger of an operator of the keyboard. The key switch is an element mounted on the keyboard. There are two major types of key switches.
The first type is a mechanical-type key switch. Such a mechanical-type key switch will click if the key top is pressed efficiently. The click becomes an important signal to an operator. Moreover, each of the key switches can be repaired individually when it is broken. However, such key switches are operatively mounted on a printed circuit board mounted on a keyboard by means of soldering, thus involving sophisticated work which results in high cost.
The second type is a film-type key switch including a lower film mounted on a keyboard, a film insulator mounted on the lower film, and an upper film mounted on the film insulator. A lower surface of the upper film is printed with a first circuit including a plurality of contacts. The film insulator defines a corresponding number of apertures. An upper surface of the lower film is printed with a second circuit including a corresponding number of contacts. A silicone rubber membrane is mounted on the keyboard. A plurality of hollow seats project from an upper surface of the silicone rubber membrane. Each of the hollow seats includes a top and a periphery. A protrusion projects from a lower surface of the top of each of the hollow seats. One of the contacts of the first circuit will be engaged with one of the contacts of the second circuit through one of the apertures defined in the film insulator by means of the protrusion projecting from one of the hollow seats if the hollow seat is pressed. Such key switches involve simple work, thus resulting in low cost. However, each of such key switches will not click when it is pressed, therefore, will not send a signal to an operator. Furthermore, the whole film from which the hollow seats project will have to be removed if one of the hollow seats is broken.
This invention is intended to solve the above-mentioned problem by merging the advantages of the two above-mentioned types of key switches.